Excess melanin production by melanocytes is associated with a variety of skin pigmentation-related disorders, including melasma and age spots. In melasma, excessive production of melanin results in black deposits in melanocytes present in the epidermal skin layer. Melasma is one of the leading refractory diseases occurring in the skin of women. Melasma often occurs in pregnant women and in women who are taking oral or patch contraceptives or undergoing hormone replacement therapy.
Tyrosinase is an oxidase that is the rate limiting enzyme in the synthesis of melanin and is therefore an important therapeutic target for agents that reduce hyperpigmentation and treat skin pigmentation-related disorders. In humans, the tyrosinase enzyme is encoded by the TYR gene. Mutations in the TYR gene that result in impaired tyrosinase production lead to type I oculocutaneous albinism.
Currently available treatments of skin pigmentation-related disorders associated with excessive melanin production include hydroquinone, arbutin, tretinoin, azelaic acid, kojic acid, chemical peels and microdermabrasion. However, such treatments are often ineffective and can have significant side-effects. Individuals with such disorders often need to resort to cosmetics to hide the areas of excessive skin pigmentation.
Thus, there is a need for improved compositions and methods for the inhibition of melanin production and the treatment of skin pigmentation-related disorders, including melasma and age spots.